| Adeleorina | |
|---|---|
 | |
| Cyst of an unidentified haemogregarine in the liver of a bat | |
Scientific classification | |
| Domain: | Eukaryota |
| Clade: | Diaphoretickes |
| Clade: | SAR |
| Clade: | Alveolata |
| Phylum: | Apicomplexa |
| Class: | Conoidasida |
| Order: | Eucoccidiorida |
| Suborder: | Adeleorina |
| Families | |
Adeleidae | |
Adeleorina is a suborder of parasites in the phylumApicomplexa.[1]
Léger proposed this taxon in 1911. The first species identified wasDactylosoma ranarum by Lankester (1871) in a frog in Europe. It was initially calledUndulina ranarum, but this was changed in 1882 toDrepanidium ranarum. This species was subsequently moved to the genusDactylosoma.
Canine hepatozoonosis was first described inIndia in 1905 by James. The organism was namedLeukocytozoon canis. The vector was identified in 1907 by Christopher to be the brown dog tick (Rhipicephalus sanguineus). The genusHepatozoon was created by Miller in 1908 for a parasite of the white rat (Rattus norvegicus) that underwentmerogony in theliver andsporogony in themiteLaelap echidinus. Ledger initially placed this genus in the familyHaemogregarinidae, but Wenyon subsequently removed it and placed it in the newly created taxonHepatozoidae in 1926.
All species in this suborder use thesyzygy method ofgamete formation. This involves the association of often motilegamonts prior to the formation of functional gametes and fertilization.
Their life cycles tend to be complex, involving at least one (and often several) asexual cycles ofmerogony followed bygametogony,syngamy andsporogony. In many species of the group, themeronts andmerozoites have morphologically distinct types: one type of meront produces large merozoites which initiate a further round of merogonic replication; a second produces smaller merozoites which are the progenitors of thegamonts.Microgamonts produce usually only one to fourmicrogametes. Other characteristic features include the absence ofendodyogeny and the enclosure ofsporozoites in asporocyst.
In haemogregarines withheteroxenous species,conjugation of gamonts and subsequent sporogony usually occurs within an invertebrate (definitive host), which also serves as thevector. Merogonial division usually takes place in the parenchymatous organs of the vertebrate host. This is followed by the formation of infective gametocytes in the erythrocytes. In the genusHepatozoon, gametocytes are also formed in the leukocytes.
The haemogregarines use two modes of transmission:
Adeleorina has about 500 species, which have been organised into seven families and 19 genera. The families have been divided into two groups:
One exception to this classification is known:Klossiella (familyKlossiellidae) is a monoxenous coccidium ofmammals andreptiles.
The taxonomy is this group may be incorrect as theHepatozoidae appear to be paraphyletic.[2] The genusHemolivia appears to lie within the genusHepatozoon.[3] The genusHepatozoon appears to have two subgenera with one in the carnivorous mammals and the other in lower vertebrates and rodents.[4]
The families in this suborder are:
Karyolysus infects lizards (Lacerta) and possibly scincids.Haemogregarina infects turtles and leeches. Species of the genusDesseria infect fish and lack erythrocyticmerogony. The genera in the subfamily Ithaniinae share a number of morphological features and infect the digestive tract of insects.
DNA studies suggestHemolivia may lie within theHepatozoon clade.[3] If this can be confirmed, the taxonomy of this group will need revision. A study of the 18s rRNA gene suggests that there may be some overlap betweenKaryolysus andHepatozoon.[6]
Karadjian, Chavatte and Landau revised theAdeleidae in 2015,[7] performed a molecular analysis and proposed a new classification in four 'types' based on their biology, as follows:
